Coiling method and apparatus

ABSTRACT

A coil made of a continuous piece of elongated material such as tubing, prebent into pancakelike spirals called radial layers, each radial layer made up of several concentric and coplanar convolutions, with several radial layers stacked axially, and method and apparatus for making such coils. The material is bent prior to coiling at predetermined bending radii which are different for different convolutions within a radial layer. One or more of the convolutions within each radial layer may be bent at constant bending radius; the rest may be bent at gradually changing radii. The bending radius is controlled by an electric and hydraulic network employing both timed and feedback controls. The coil may be built either upwardly, with the most recently made radial layer always at the bottom of the coil, or it can be built downwardly, with the most recently made radial layer always on the top of the coil.

[ Feb. 8, 1972 54] COILING METHOD AND APPARATUS [72] Inventors: Herbert J. Meyfarth, Cleveland, Ohio,

John J. Crosby, Cambria Heights, NY.

[73] Assignee: Republic Steel Corporation, Cleveland,

Ohio

[22] Filed: May 12, 1969 21 Appl.No.: 823,764;

52 u.s.c1 .Q ,;....7 2/,13s, ,24'2" si 51 1m.c1. ...n21r3/i0,B2 1-4-7/00 [58] FieldofSearch ..72/l38,l35;242/83 [56] References Cited UNITED STATES PATENTS 2,179,389 11/1939 Turner 72/138 3,l45,760 8/1964 Brautigam 72/1 38 3,478,399 11/1969 Wyatt ..-......242/83 FOREIGN PATENTS OR APPLICATIONS y 180,075 7/1962 Sweden ..,...242/ 83 Primary Examiner-Charles W. Lanham Assistant ExaminerRobert M. Rogers Attorney-Robert P. Wright and Joseph W. Malleck 5.71 ABSTRACT ti'r ng,'pre b ent into pancakelike spirals called radial layers, eachradiallayer madeup of several concentric and coplanar co nvolutions, iwith several radial layers stacked axially, and q lr'ijethod and apparatus for making such'coils.

I The materialis bent prior to coiling at predetermined bending radii which are different for different convolutions within a radial layer. One. or more of the convolutions within each radiv al layer may be bent at constant bending radius; the rest may V be bent at graduallychanging radii. The bending radius is controlled by an electric and hydraulic network employing both timed and feedback controls. The coil may be built either upwardly, with the most recently made radial layer always at the bottom of the coil, or it can be built downwardly, with the mostrecently made radial layer always on the top of the coil.

14 Claims, 10 Drawing figures "ade of a continuousipiece of elongated material such- SHEET 2 BF 5 COILING METHOD AND APPARATUS BACKGROUND OF THE INVENTION l Field of the Invention The invention is in the field of coiling and uncoiling continuous elongated pieces of rigid material such as tubing, rod, stripand the like which retain their shape unless prebent into a different shape. I

It is sometimes desirable to coil several hundred feet of large diameter steel tubing which must be prebent in order to stay in coil fomi. Generally used known methods of coiling are unsatisfactory, since they involve no prebending; hence a coil.

will not retain its shape unless severely constrained at all times. In the case of steel tubing used for gas mains, for example, it'is desirable to have a coil which has minimal dimensions, to facilitate transportation, but contains maximum length of tubing to reduce the number of joints in laying long conduits, and is easily handled in coil form especially in connection with uncoiling in the field.

2. Prior Art Coils of the general arrangement described in this application have been made in the past as exemplified by the U.S. Fat. to Sibley, No. 2,723,807 and the U.S. Pat. to Smith, Jr. et al., No. 3,337,154. In both patents the coiled material is bent at the point of ceiling, with the essential help of either the coil spool or the already coiled material. The material is not bent prior to coiling.

This prior art method may be useful for highly ductile materials such as soft copper, or for other materials which exhibit very weak spring characteristics. It could not be used for materials such as steel, because steel must be prebent in order to stay in coil form. Even if the yield point of the material could be exceeded by forcing it into a coil similar to that of the above patents, the force required would be so great that,

should the material be tubing, it would collapse.

Dallas U.S. Pat. No. 1,871,665 discloses a coiling machine in which strip material is bent prior to coiling, and in which the bending radius is gradually increased. There is no disclosure of the formation of convolutions of constant radius of curvature, or of multilayer coils.

Bram U.S. Pat. No. 3,195,338 shows a device for the continuous winding of wire in which single turn layers are built upwardly with the last layer always on the bottom of a coil. The building in an upward fashion of the multiturn per layer of a multilayer coil is not disclosed.

SUMMARY OF THE INVENTION The coil produced by the present method and apparatus is layers, each radial layer being a spiral of several concentric and coplanar convolutions. The radial layers are stacked axially in partially nested relationship.

In making the coil, a strand of material such as tubing which retains its shape when bent, is fed at constant speed to a bend ing station having two or more pairs of guide rolls and a bending roll. The bending roll is controlled by an electric and hydraulic network for imparting different bending radii to the tubing passed tangentially by it.

In one embodiment, the bending roll bends at constant bending radius enough material for making one complete coil convolution or turn. The bending radius is then gradually changed such that each new convolution either just encircles or is just encircled by the previously made convolution. The bending radius is then held constant for one complete convolution and then starts changing again at the same rate, but in a direction opposite to its most recent direction of change. The first constant radius convolution and the several immediately following changing radius convolutions define the first radial layer; the next constant radius convolution and the several following changing radius convolutions define the second radial layer, etc.

By rendering constant the bending radius during the making of a convolution in a layer, it is believed that an additional of curvature, and one or more intermediate convolutions having varying radii of curvature.

Still further, the bending roll may be continuously reciprocating, without ever remaining stationary, such that no convolution is of constant radius of curvature.

The coil may be supported on a plurality of radial support rollers and may be built upwardly, with newly bent tubing going on top of the support rollers but below the most recently coiled radial layer. The coil may alternatively be built downwardly, with newly bent tubing going on top of the most recently made radial layer. Further, the coil may be built in any direction.

In field use, the coil is unbent by passing the tubing through fixedly positioned straightening rolls which remove the radius of curvature. The coil is supported on a spool supplied in the field and one free end of the coiled material may be passed through a guide secured in the vicinity of the axial periphery of the coil and then through the straightening rolls. The free end is then pulled away and the coil begins unwinding. As it does so, the radial layers separate, because of the presence of the guide, and when only a few radial layers are left, the whole remaining coil starts sliding toward the guide or toward the plane of the straightening rolls, should the guide be omitted. There is no need to move the coil spool axially as material is being unwound.

The advantage of this entire coiling-uncoiling arrangement is that the coil is virtually self-contained, by virtue of the prebending, and is easily unbent and uncoiled in the field.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a top view of apparatus embodying the invention, showing a bending station and a partially completed supported layer of tubing.

FIG. 2 is a side elevational view of apparatus for uncoiling and unbending.

FIG. 2a is a partial sectional view of the apparatus for uncoiling and unbending of FIG. 2, looking in the direction of arrows 20. I

FIG. 3 is a top view showing the bending station in greater detail.

FIG. 4 is a frontal, partly elevational and partly sectional view of the bending station looking in the direction of the arrows 44 of FIG. 3.

FIG. 5 is a side partly elevational and partly sectional view of a detail of the bending station looking in the direction of the arrows S5 of FIG. 3.

FIG. 6 is a sectional view of a supported coil looking in the direction of the arrows 6--6 of FIG. 1.

FIG. 7 is a sectional view of a supported coil looking in the direction of the arrows 7-7 of FIG. 1.

FIG. 8 is a partly elevational and partly sectional view of a coil and of modified apparatus for supporting it.

FIG. 9 is a schematic diagram of electrical apparatus associated with'the bending station.

FIG. 10 is a schematic representation of hydraulic and elec trical apparatus associated with the bending station.

DETAILED DESCRIPTION The subject invention may be used in coiling and uncoiling any elongated material such as tubing, rod, wire, strip, etc. For

the sake of brevity, however, reference will be made only to tubing as the material subjected to bending and unbending, it

being understood that any other elongated material may be subjected to the same processing or to processing within the scope of the invention.

THE COIL The coil produced by the present method and apparatus is made of a continuous piece of tubing. The coil consists of a number of pancakelike layers which are stacked. Each pancake layer is a spiral made up of several concentric and coplanar convolutions of tubing. The pancakelike layers are referred to herein as radial layers. A single radial layer made up of convolutions 20a, 20b, 20c and 20d is visible in FIG. 1. The coil as made is supported on rollers, so that it revolves as it is being formed.

Each convolution of tubing within a radial layer has a different radius of curvature. In the making, a radial layer can be started either with the innermost convolution, that is, the one with the smallest radius of curvature, or else with the outermost convolution, the one with the largest radius of curvature, or else with any intermediate convolution. A coil which is started with an end convolution, say the outermost convolution, will be described.

Suppose that a radial layer is started with the outermost convolution (20a in FIG. 1). A straight length of tubing equal to the circumference of the convolution 20a which is to be made is bent to the desired (e.g., constant) radius of curvature. It should be noted here that the curvature to which the tubing is being bent by bending apparatus is usually somewhat different from the curvature of the convolution which finally results, because the resiliency of the tubing tends to straighten it somewhat after the bending force is removed.

Because of this difference, bending radius is used herein to mean the radius of curvature at which the tubing is bent, and radius of curvature of a convolution is used to mean the radius of curvature of the convolution after it has had a chance to straighten somewhat following removal of the bending force.

In making the coil, a length of material is bent, typically although not necessarily at constant bending radius, and makes up a circular convolution which is the outermost convolution 20a of the radial layer visible in FIG. 1. Following that, the bending radius is gradually decreased such that the next convolution 20b will be just encircled by the outermost convolution 20a. The bending radius is gradually decreased still more such that the next convolution 200 will bejust encirclcd by the previously made convolution 20b, and the next convolution 20d will bejust encircled by 20c.

The bending radius is then held constant during the making of the next complete convolution following 2011. Thus at the end of the convolution labeled 20d and at the start of the next convolution a transition takes place: one radial layer is completed and another one is started. The tubing making the innermost convolution 20d of the completed layer now gradually becomes the tubing making the innermost convolution 22d (see FIG. 7) of a second radial layer which can be either above or below the first layer (below in FIG. 7). Although a radial layer having only four convolutions is used as an example, it should be evident that any number of intermediate convolutions may be made between the outermost and innermost convolutions ofa radial layer.

In the second layer, as seen in FIG. 7, the innermost convolution 22d is made first, at constant bending radius, then another convolution 220 is made at an increasing bending radius such that is just encircles the innermost convolution 22d, then another convolution 22b which just encircles the previously made convolution 22c, then another convolution 2211 which just encircles 22b. After the convolution 22a is completed, the bending radius is held constant and another transition takes place between tubing making the outermost convolution 22a of the second layer and tubing making the outermost convolution 23a of a third layer. The convolution 23a is made at constant bending radius.

The process asjust described may continue until the coil has achieved the desired size. As shown in FIG. 7, the coil is built upwardly; it could just as well be built downwardly or in any other direction. At another cross section, however, the convolutions in one layer may be directly over the corresponding convolutions of the adjacent lower radial layer and directly under the corresponding convolutions of the adjacent upper radial layer. Complete nesting is not possible because, as between two adjacent radial layers, one is in effect a left-hand spiral and the other one is in effect a right-hand spiral, and crossing over of convolutions must take place Because of some shifting of radial layers due to the weight of the coil, however, partial nesting of convolutions of one layer occurs between adjacent convolutions in adjacent layers.

In the coil described above it has been mentioned that constant radius bending may be employed to produce turns (outermost and innermost) of constant radii of curvature. The utilization of constant bending radius of outermost and innermost turns is desirable because it is believed to increase the length of tubing that can be placed in a coil layer of a given dimension over the length of tubing that may be accommodated within a layer of the same dimensions if the bending radius changes continuously and is not held constant. However, it is feasible, of course, to make a coil in which bending radius changes continuously e.g., increasing then immediately decreasing then immediately increasing, and so forth), so that the radius of curvature continuously varies in the turns of all layers.

BENDING The apparatus for bending and coiling is generally illustrated in FIG. 1, which shows tubing 20 coming from the lefthand side of the drawing toward a bending station 21.

The tubing may be supplied from standard forming and welding tube making apparatus which takes up a coil of flat steel strip, bends it into a long cylinder, welds the free edges, and partly shaves off the welding bead for smooth circular cross section. The tubing is forced out of such apparatus at constant speed.

Since the newly made tubing is forced toward the bending station 21, the column strength of the tubing is usually sufficient for driving it through the bending station. Should the column strength of some tubing be insufficient, appropriate auxiliary driving means (not shown) may be installed at or near the bending station 21.

The bending station 21 has thejob of bending the tubing 20 at appropriate bending radii for the making of the coil as previously described. In particular, the bending station 21 must bend the tubing lengths for making up different convolutions within a radial layer at different bending radii, at least one of which is constant and the rest of which gradually change as the tubing for particular convolutions are being bent. Alternatively, the bending radius may continuously change.

After leaving the bending station, the newly bent tubing 20 is passed under a support roller which is a cylinder mounted for free rotation about a horizontal axis, after which the tubing 20 passes over similarly mounted support rollers 89, 90, 86, 87 and 88. The tubing 20 then goes over the roller 85.

The bending station 21, best seen in FIGS. 3, 4 and 5 has a rigidly supported heavy baseplate 28 over which an intermediate plate 29 is pivotally mounted. The pivot point is at a shaft 40 which extends through the baseplate 28 into an appropriate rigid support (not expressly shown). Pivoting motion of the intermediate plate 29 is carried out by means of a bolt 30 having one end pivotally attached to a spindle 301 secured to the top of the intermediate plate 29 and having a threaded shank which goes through a bore in the upstanding section of an L-shaped brace 31, the horizontal section of which is secured to the baseplate 28. Nuts 32 and 33 are threaded onto the shank of the bolt 30, one on each side of the brace 31.

By loosening one of the nuts 32 and 33 and tightening the other, the intermediate plate 29 is caused to pivot about the shaft 40. The pivoting of the intermediate plate 29 is for the purpose of initially adjusting the bending station for tubing of different diameters and different elasticity characteristics. Once adjusted, the intermediate plate 29 would not normally change its position in relation to the baseplate 28 throughout a production run so long as the characteristics of the steel strip used to make the tubing remain reasonably constant.

The baseplate 28 also supports two pairs of guide rolls: a pair made up of rolls 34 and 35 and a pair made up of rolls 36 and 37. The rolls are coplanar and have peripheral grooves which cooperate to provide a confining tangential passageway for the tubing 20. Different guide rolls can be used for different diameter or different shape tubing. Each of the guide.

rolls is mounted for free rotation on a shaft carried by a support such as supports 38 visible in FIG. 4. Each of the supports 38 has a bottom flange 381 which fits within guide rails 39 for sliding perpendicularly to the direction of feed of the tubing 20 for accommodating different size tubing.

As best seen in FIG. 4, the shaft 40 extends through the baseplate 28 and upwardly through the intermediate plate 29 and has a sleeve 41 fitted on it for free rotation immediately over the intermediate plate 29. The inner diameter of the sleeve 41 is only slightly larger than the outside diameter of the shaft 40. A horizontal pivot arm 42 extends from the sleeve 41 and carries a downwardly extending cylinder 43 having a vertical cylindrical axis, and an upwardly extending shaft 44 along the axis of the cylinder 43.

A sleeve 45 is also received on the shaft 40 similarly to the sleeve 41, but is positioned on top of the sleeve 41. The sleeve 45 carries a transverse arm 451 extending partially along the pivot arm 42. The arm 451 is fixed at different positions relative to the pivot arm 42 by means of a bolt 46 threaded into an appropriately threaded bore of the sleeve 45 and having its head on the other side of an arcuate slot 47 cut through the pivot arm 42. The arc of the slot 47 has a radius centered at the shaft 40. The arm 451, extending from the sleeve 45 has a groove 48 for accepting tangentially and directing the free end of the tubing 20 as it first appears in the feed direction.

The shaft 44 carries, above the pivot arm 42, a bending roll 49 fitted tightly for free rotation, above the shaft 44. The roll 49 has a peripheral groove similar to that of the guide rolls. Differently sized bending rolls can be used for tubing of different sizes.

The cylinder 43 extending below the pivot arm 42 has at its bottom periphery, as best seen in FIG. 5, a tongue 50 which carries fixedly an upwardly extending spindle 51. A cam follower wheel 52 is fitted tightly over the spindle 51 for free rotation.

The periphery of the cam follower 52 is in the plane of the uniformly slanted side of a horizontal wedge shaped linear cam plate 53 which is rigidly mounted on a shim block 54. The shim block 54 is in turn rigidly mounted on a guide plate 55. The guide plate 55 slides between guide rails 56 along the feed direction of the tubing 20. The guide rails are rigidly mounted on the intermediate plate 29.

For the purpose of moving the cam plate 53, the guide plate 55 is connected to a shaft 57 which is parallel to the guide rails 56 and whose other end is connected to the piston inside a hydraulic cylinder 58. The cylinder 58 is a two-way device of standard design and can move its piston, and hence the guide plate 55 and the cam plate 53, in either direction along the guide rails 56.

The cylinder 58 is mounted on the intermediate plate 29 by means of brackets 59, shim blocks 60 and bolts 61. Two hydraulic conduits 73 and 75 which are shown only in FIG. 10 (schematically) go into the ends of the cylinder 58.

The intermediate plate 29 also supports electrical limit switches 62 and 63 which have, respectively, pivotedarms 64 and 65, each carrying at the free end a cam follower wheel 641 on a standard mount allowing for free rotation. The arms 64 and 65 are spring biased such that the switches are normally open circuits. However, when the cam plate 53 is at an extreme position along its path, one of the arms 64 and 65 is moved from its spring biased position to close the circuit of its switch by means of vertically extended striker plate 66 mounted on the cam plate 53, which contacts a cam follower wheel 641.

BENDING RADIUS CONTROL The operation of the hydraulic cylinder 58, and hence the movement of the cam plate 53 which changes the bending radius of pivoting the bending roll 49, are controlled by the electric and hydraulic networks illustrated schematically in FIGS. 9 and 10.

FIG. 10 shows primarily the hydraulic controls. All elements indicated thereon by reference numerals are of standard design; therefore, they are shown only schematically. The arrow 67 indicates an incoming working fluid conduit connected to a conventional source of fluid under pressure sufficient to move the piston inside the hydraulic cylinder 58. The arrow 68 indicates the drainage hydraulic conduit which carries fluid to a storage tank at a lower pressure.

The incoming fluid goes into a standard four-way valve 69 which has two working fluid outlet conduits 70 and 71. The incoming flow over conduit 67 can be selectively delivered into any one of the conduits 68, 70 and 71.

The conduit 70 goes into a standard flow control and check valve 72, the purpose of which is to allow, in one direction, full flow exceeding certain pressure, for the purpose of driving a hydraulic piston, and to allow only partial flow in the opposite direction, for the purpose of venting a hydraulic cylinder. A conduit 73 goes from the outlet of the check valve 72 into the left-hand side of the hydraulic cylinder 58. The conduit 71 goes into a similar check valve 74 the outlet of which is connected by means of conduit 75 to the right-hand side of the hydraulic cylinder 58.

Solenoids 76 and 77, of standard design, are operatively connected to the four-way valve 69. When neither of the solenoids 76 and 77 is energized, the four-way valve 69 delivers the incoming fluid directly to the drainage conduit 68 and there is no differential pressure on the piston inside the hydraulic cylinder 58. When the solenoid 76 is energized, the four-way valve 69 delivers the fluid coming over the conduit 67 to the conduit 71, and the fluid eventually reaches the right-hand side of the hydraulic cylinder 58, acts on the piston inside it, and causes the shaft 57 to move in an outward stroke. Fluid exhausts from cylinder 58 through conduit 73, valve 72 and connected conduits 70, 68 in valve 69. When the solenoid 77 is energized, the valve 69 connects the conduits 67 and 70, and the working fluid reaches the left-hand side of the hydraulic cylinder 58 and causes the piston therein and the shaft 57 to move in an inward stroke. Fluid exhausts through conduit 75, valve 74 and connected conduits 71, 67 in valve 69. The solenoids 76 and 77 are controlled by the electrical network illustrated schematically in FIG. 9, in which the switches 62 and 63 are the limit switches shown in FIG. 3, and solenoids 76 and 77 are the same elements shown in FIG. 10.

FIG. 9 also shows two standard relays. One relay includes a field winding 78 and contacts 781, 782 and 78-lT; the second relay includes a field winding 79 and contacts 79-1, 79-2A, 79-23 and 79-IT. The two relays are identical in construction and in each, when the field windings are deenergized, the contacts identified by the suffix 1 are open and the contacts identified by the suffix 2 are closed. When the field windings are energized, the contacts identified by suffix l are closed and the contacts identified by suffix 2 are open. The contacts 78-IT and 79-IT are timed contacts; contacts 78IT close at a predetermined time after the energizing of winding 78 and open simultaneously with the deenergization of that winding; contacts 79-IT close at a predetermined time after the energizing of the winding 79 and open simultaneously with the deenergization of that winding.

The circuit of FIG. 9 is connected to a suitable potential source, e.g., 110 volt AC and has a main off-on switch 80 as well as an auxiliary starting switch 81. The circuit operates in the following manner:

Assume that the main off-on switch 80 is closed at a time when limit switches 62 and 63 are open. Starting switch 81 is manually closed momentarily and current flows through the normally closed contacts 79-2A and 78-2 and through the winding 79. The winding 79 is energized and the contacts '79-1 close while the contacts 79-2A open. Winding 79 remains energized through now closed contacts 79-1 and normally closed contacts 78-2. 9

With the main off-on of the winding 79, the delay interval of the timed contact 79-lT commences. After the predetermined time delay, the timed contacts 79-lT close, energizing the solenoid 77. The energization of the solenoid 77 causes working fluid to be delivered to the left-hand side of the hydraulic cylinder 58, and the shaft 57 begins moving the cam plate 53 inwardly toward the right in FIGS. and 3. The shaft moves steadily until, as seen in FIG. 3, the striker plate 66 contacts and pivots the arm 65 of the limit switch 63, thus causing the limit switch 63 to close and to energize the relay winding 78.

The energization of the relay winding 78 causes contacts 78-1 to close and contacts 78-2 to open. The opening of the contacts 782. cuts off the current through the relay winding 79 which in turn causes the contacts 79-lT to open, deenergizing solenoid 77 and ceasing inward movement of shaft 57. The closing of contacts 78-1, along with the now closed contacts 79-2B, establishes a current path parallel to the switch 63 which pro ides for continued energization of relay winding 78 regardless of whether switch 63 is open or closed. The solenoid 76 is not yet energized because of the time delay of the timed contacts IS-IT. At this time there is no differential pressure in the hydraulic cylinder 58, and the piston therein is stationary.

After its predetennined time delay, the contacts 78-IT close, causing the solenoid 76 to be energized. This causes working fluid to be directed to the right-hand side of the hydraulic cylinder 58, and the cam plate 53 begins moving outwardly, away from the hydraulic cylinder 58. The cam plate 53 moves steadily until the striker plate 66 contacts and pivots the arm 64 of the limit switch 62. The limit switch 62 is thus closed, and the closing energizes the relay winding 79 which in turn opens the contacts 79-2B, cutting off the current through the relay winding 78. The winding 79 remains energized through contacts 79-1 and 78-2.

Relay winding 78 is now deenergized, which causes the opening of contacts 78-1 and 78-1T, thus also deenergizing the solenoid 76. Both solenoids 76 and 77 are again deenergized; the cam plate 53 stays at its outermost position for the duration of the predetermined time delay of the contacts 79-1'11 When the time delay is over, the solenoid 77 is energized and the cam plate 53 begins moving inwardly toward the hydraulic cylinder 58.

The in and out movement of cam plate 53 described above is repeated for as long as the off-on switch 80 remains closed.

COIL SUPPORT The coil support mechanism is illustrated in FIGS. 1, 6 and 7 which show a pair of stationary support beams 82 and 83 crossing orthogonally at the axis of the finished coil and held together by appropriate bracing structure generally indicated at 84. Each of the beams 82 and 83 carries three cylindrical support rollers, two at one end, and one at the other end. The beam 82 carries a support roller 85 at its end closest to the bending station 21, and support rollers 86 and 87 at its other end; the beam 83 carries a support roller 88 at its end closer to the bending station 21 and support roller 89 and 90 at its other end.

All support rollers are mounted on their respective beams for free rotation about their cylindrical axes by means of appropriate brackets 91 whose bottom ends rest on a support.

Additional brackets 92 are employed for rotational support of the rollers 86 and 87 and the rollers 89 and 90. In horizontal cross section, the brackets 91 are outwardly facing channel sections. A vertical roller 91-a is attached for free rotation to each of the brackets 91, at the inside of the channel, for the purpose of preventing the coil from slipping off the support rollers.

As best seen in FIGS. 6 and 7, the support rollers are mounted in different horizontal planes. The roller is at the highest level, the roller 88 is at the next lower level, the rollers 86 and 87 are in a common plane and at the next lower level, and the rollers 89 and are in a common plane at the lowest level. The support rollers carry the most recently bent radial layer of tubing, since the coil is pushed upwardly as it is built.

An alternative supporting mechanism is illustrated in FIG. 8 which shows a basket 93 which supports at its bottom the first made radial layer of tubing. The basket 93 has, at its bottom, lockable coasters 94 of which only two are shown. The coasters 94 rest on a flat circular plate 95 having a smaller concentric ring 96 attached to its bottom.

The ring 96 rests upon a roller bearing 96a appropriately supported by a top flange 97 of a heavy shaft 98, so that the plate 95 can rotate as bent tubing is deposited in the basket 93. The shaft 98 extends upwardly from the piston of a heavy underground hydraulic cylinder 99. A circular depression 100, slightly larger in diameter than the plate 95. is cut into the ground surface 101 to accommodate the plate 95 when it is brought, by the action of the hydraulic cylinder 99, to the ground level. The top of the plate 95 is thus flush with the ground surface 101, and the basket 93 can be rolled away on the coasters 94, after unlocking the coasters.

COlLlNG An example will be given new of producing a coil formed of three radial layers.

Tubing 20 is fed toward the bending station 21. The free end of the tubing is inserted between the opposing guide rolls 34 and 35, and then between the guide rolls 36 and 37. The free end of the tubing 20 next strikes tangentially the groove 48 of the arm 451 visible in FIG. 4 and then goes tangentially into the peripheral groove of the bending roll 49.

Assume that both solenoids 76 and 77 are deenergized, that the cam plate 53 has just reached the position closest to the hydraulic cylinder 58 and that the time delay interval of timed contacts 78-1T hasjust commenced.

Since solenoids 76 and 77 are deenergized, there is no differential pressure on the piston inside the hydraulic cylinder 58, and the cam plate 53 is stationary. As the tubing 20 is fed past the bending roll 49, it is bent at a constant bending radius. The intermediate plate 29 has been pivoted about the shaft 40 by means of bolt 30 and nuts 32 and 33 such that the bending radius at this position of the cam plate 53 results in the desired radius of curvature of the outermost convolution of the coil that is to be made.

The tubing 20 thus proceeds tangentially past the bending roll 49 and is bent at a constant bending radius for as long as necessary to bend the length of tubing required for the outermost coil convolution 20a. This length of time is defined by the predetermined time delay of the timed contacts 78-1T.

As the free end of the tubing 20 moves away from the bending roll 49, it is first passed under the support roller 85. When the free end reaches support roller 89, it is passed over it, and then over support rollers 90, 86, 87 and 88. When the free end of the tubing 20 again reaches the roller 85, it is passed over it and goes over the roller 85 at every subsequent convolution. The tubing coming from the bending station 21, however, always passes first under the roller 85.

As soon as the delay interval of the contacts 78-1T is over the convolution 20a, as shown in FIGS. 1, 6 and 7 has been made and the solenoids 76 is energized. Uniform fluid flow is now delivered to the right-hand side of the hydraulic cylinder 58 and the cam plate 53 begins moving outwardly, away from the hydraulic cylinder 58, at a steady rate and begins changing the bending radius. The taper of the cam plate 53 and its rate of motion are such that the change of bending radius will result in changes of radii of curvature of the completed convolutions necessary to nestle each convolution of the radial layer that is being made inside the previously made convolution. Different cam plates may be used for tubing of different diameters or of different metals.

As the final convolution d of the first radial layer is completed, the striker plate 66 contacts the limit switch 62, closes it, and thus causes the solenoids 76 to be deenergized, thereby stopping outward movement of the cam plate 53. The time delay interval of timed contacts 79-1T is initiated as described above. The time delay of the contacts 79-1T is set such that one complete convolution is made at a constant bending radius.

At the time of starting the constant bending radius period (the beginning of the time delay interval), a transition takes place between the first radial layer and the second radial layer.

The convolution 20d of the first radial layer is made at a steadily. decreasing bending radius and nestles inside the previously made convolution 200, as noted above, but the next convolution, the convolution 22d, is bent at a constant bending radius and cannot nestle inside the convolution 20d. Since the tubing for making the convolution 22d is coming from under the support roller 85, and cannot fit inside the circle of the convolution 20d, it pushes up the convolution 20d and fits under it, remaining somewhat offset toward the center of the coil. The second radial layer is thus begun by the tubing for the convolution 22d going under (pushing up) the first radial layer.

As soon as the delay interval of the timed contacts 79-1T is over, the solenoid 77 is energized and the cam plate 53 begins moving inwardly, toward the hydraulic cylinder 58 and decreases gradually and uniformly the bending radius. The second radial layer continues being built by tubing 20 coming from underneath the roller 85 and being pushed between the first radial layer and the rollers 89 and 90. While the first radial layer was built from the outermost convolution inwardly toward its innermost convolution, the second radial layer is built outwardly from its innennost convolution.

The making of the second layer continues through the time the striker plate 66 reaches the limit switch 63. Then, after the completion of the convolution 22a, the solenoid 77 is deenergized and the movement of the cam plate 53 stops. The time delay interval of the contact 78-1T now begins, and the cam plate is stationary for a time interval sufficient to make one complete coil convolution (23a).

At or about the time the constant radius convolution is started, another transition takes place, this time a transition between the second radial layer and the third radial layer.

When the convolution 23a is started, it cannot encircle the previously made convolution 22a. The radius of curvature of convolution 23a does not increase, because the bending radius for convolution 23a is held constant. Thus, the newly bent tubing for the convolution 23a forces itself under the convolution 22a and a little to the outside of it, as best seen in FIG. 7.

When the predetermined delay interval of the timed contact 78-1T is over (completion of convolution 23a), the solenoid 76 is again energized and the cam plate 53 begins moving outwardly, away from the hydraulic cylinder 58. The third radial layer is now being made of tubing being pushed under the support roller 85 and between the second layer and the support rollers 89 and 90 to make convolutions 23b, 23c and 23d.

The process described above is repeated until the desired number of radial 'layers has been formed.

In the coiling process just described, in each radial layer one convolution is bent at a constant bending radius and the remaining convolutions are bent at constantly decreasing or constantly increasing bending radii. It is possible, however, to produce a coil by bending both the outermost and the innermost convolutions of each radial layer at two different but constant bending radii and bending any intermediate convolutions within a radial layer at either decreasing or increasing bending radii. This modification can be accomplished simply by adjusting the time delays of contacts 78-1T and 79-1T of FIG. 9 such that the cam 53 stops at each of its extreme positions for a time interval long enough for making two (or even more) complete convolutions.

Alternatively, the timed contacts 78-1T and 79-lT may be adjusted to zero delay, or relays which have no timed contacts may be employed, so as to make the cam 53 reciprocate without stopping at either extreme of its movement. The resulting coil will be composed of convolutions all of which have a varying radius of curvature.

Further, the cam plate may be contoured nonlinearly so as to vary nonlinearly the bending radius.

When the alternative support mechanism illustrated in FIG. 8 is used, the only major difference is that the coil is being built downwardly instead of upwardly. As bent tubing leaves the bending roll 49, it first goes onto the bottom of the basket 93 which is positioned at that time just below the horizontal level of the bending roll 49. As the buildup of radial layers progresses, the basket 93 is dropped further and further downwardlyby controlling the pressure inside the hydraulic cylinder 99 through conventional means.

When the desired number of radial layers is completed, the top of the support plate is brought flush with the ground surface 101 and the basket 93 is rolled away on its coasters 94 to a site for further processing of the coil.

It should be noted that when a coil is built upwardly (each layer going beneath the previously formed layer) the length of material emerging from the bending station takes a large portion of the entire weight of the coil thereabove, since the coil is being raised upwardly as it is being built. On the other hand, for a coil being built downwardly (each layer going above the previously formed layer) no raising of the coil is involved. Hence in this latter case each turn in the coil only takes the weight of the turns directly thereabove. As a result, larger sized coils can be built downwardly rather than upwardly. The advantage gained by building a coil upwardly is that significant space beneath the bending station need not be taken. in some environments, space beneath a bending station may not be available, necessitating the upward building of coils.

Steel tubing has been coiled in accordance with the invention. For example, steel tubing of 2% inches outside diameter and a wall thickness of 0.072 inch has been coiled. Coils have been formed with about 700 feet of tubing making up a single coil. Coils have been formed with radial layers of about four turns or convolutions per layer. Coils have been formed 10 radial layers in height and built upwardly, i.e., each layer as produced was positioned beneath the layer previously produced. The length of tubing in a single layer of the coil depended upon whether the layer was formed with a turn of con stant bending radius on the inside or the outside of the layer. Those layers having turns of constant radius of curvature on the inside of the coil included less footage of tubing per layer than those layers having turns of constant radius of curvature at the outside of the coil. Coils so produced have been wrapped with cardboard and strapped with about three straps for shipment.

UN COILING After a coil is produced as described heretofore, it may be subjected to further processing such as coating with plastic, testing for strength and continuity, wrapping, etc.

When the time comes to use tubing from the coil, such as for example in gas main laying, the tubing must be straightened by removing the radius of curvature of each convolution. Otherwise, uncoiled tubing would spring back to its coiled form if not restrained.

One example of apparatus for straightening coiled tubing is shown in FIGS. 2 and 2a.

FIG. 2 shows a part of a land vehicle 102 which may be a standard pipe laying rig carrying at its rear end a plow 103.

The plow 103 is slidably mounted and can be raised to clear the ground surface or lowered to plow at a suitable depth by the use of mechanisms well known in the field of gas main laying. A pair of parallel beams 104 (only one shown) is pivotally attached to the plow at a pivot shaft 105 and extends away from it at a 30 to 45 angle from the horizontal. The beams support for free rotation a removable spool 106 mounted on an axle 1061 perpendicular to the beams 104 and received into appropriate bores therein.

A pair of hydraulic cylinders 107 (only one shown) extends, one from the lower portion of each beam 104, to a support 108 carried by the vehicle 102. The cylinders 107 are two-way devices and can raise or lower the beams 104 and the spool 106 by use of standard hydraulic controls. The spool 106 carries a coil 109 wound in accordance with the preceding description.

As seen in FIG. 2a, an artn 110 extends from the free end of the beam 104 toward the other beam 104, and a shaft 111 carrying at its free end a peripherally grooved guide roll 112, extends from the free end of the arm 110 toward the axis of the spool 106.

The free end of the coiled tubing is passed between beam 104 shown in FIG. 2a and the guide roll 112, tangentially to the groove of the roll 112, such that the tubing fits into the groove of the guide roll. The free end is then passed between opposing guide rolls 113 and 114, tangentially to the grooves of guide rolls 115 and 116 and through the passageway between straightening rolls 117, 118 and 119. The guide rolls 113 through 116 and straightening rolls 117, 118 and 119 are mounted rotatably in the plow 103.

The free end of the tubing is pulled through its path past the guide rolls by means of a cable 120 and a suitable gripping device 121. The straightening rolls 117, 118 and 119 are disposed in a triangular pattern appropriate for substantially removing the radius of curvature of the tubing passed between them. The straightening roll 119 may be vertically slidable and lockable into any position along its path so as to exert different predetermined straightening forces on the tubing.

As tubing is withdrawn from the coil by pulling on the cable 120, convolutions and radial layers are removed from the coil 109. The remaining radial layers tend to separate from each other because of the axial pull due to retention by the guide roll 112 of the convolution which is being straightened. When only a few radial layers are left in the coil, the whole coil may begin sliding toward the guide roll 112. There is no need at any time for axial movement of the spool 106.

The guide roll 112 may be omitted and one of the free ends of the coil 109 may be fed directly to the guide rolls 113, 114, 115 and 116 and then to the straightening rolls 117, 118 and 119.

We claim:

1. A method of coiling elongated material comprising the steps of:

a. supplying a continuous length of the material at constant speed;

b. bending the material prior to its reaching its final position in the coil at constant bending radius until one complete convolution of bent material has been made;

c. bending a subsequently supplied length of material at a bending radius varying linearly with time until at least one additional convolution made in the course of step (b) is made, whereby a radial layer is formed of the convolutions made in the course of steps (b) and (c); and

d. bending a subsequently supplied length of material at constant bending radius different from that of step (b) until one complete convolution of a second radial layer has been made.

2. A method of coiling continuous elongated material as defined in claim 1 comprising the additional subsequent step of:

e. bending a continuous length of material at a bending radius varying linearly with time at the same rate as in step (e) but in a sense opposite to that of step (c) until at least another complete convolution has been made coplanar and continuous with the convolution made in the course of the step (d).

3. A method of coiling elongated material comprising the steps of:

a. bending a continuous length of material at a varying bending radius until one or more convolutions have been completed; and

b. next bending a length of material continuous with the length of step (a) at a constant bending radius.

4. A method as defined in claim 3, wherein the constant bending radius of step (b) is the same as the last value of varying bending radius of step (a).

5. A method of coiling continuously supplied tubing into a continuous coil comprising the steps of:

a. bending a length of tubing into a plurality of coplanar convolutions to make a first radial layer;

b. concurrently supporting said first radial layer in a substantially horizontal plane;

. subsequently bending a length of tubing into a plurality of coplanar convolutions to make a second radial layer sub stantially of the same radial dimension as the first radial layer; and

d. concurrently with step (c), positioning the convolutions of the second radial layer below the first radial layer. with each convolution of tubing in the second layer bearing against and pushing upwardly at least one convolution of tubing in the first layer whereby the coil is built in the upward direction.

6. A method of coiling tubing as in claim 5, including the additional subsequent step of bending tubing into additional pluralities of convolutions for making additional radial layers, each substantially of the same radial dimension as that of previously made radial layers, and positioning each radial layer below the previously made radial layer in the same manner as the second radial layer was positioned underneath the first radial layer.

7. Apparatus for coiling continuously supplied elongated material comprising:

a. means for bending the supplied material at predetermined bending radii; and

b. control means for alternately keeping the radius at which the bending means bends the material constant for predetermined periods of time and varying for predetermined periods of time.

8. Apparatus for coiling continuously supplied elongated material as defined in claim 7, wherein the bending means comprises:

a. means for confining the supplied material to a fixed path;

b. means for deflecting the supplied material from its path as it leaves the confining means; and

c. means for moving the deflecting means to different positions relative to the confining means.

9, Apparatus for coiling continuously supplied material as defined in claim 8 wherein the confining means comprises:

a. at least one opposed pair of guide rolls defining between them a passageway for the supplied material; and

b. the deflecting means includes a bending roll.

10. Apparatus for coiling continuously supplied material as defined in claim 9 wherein:

a. the means for moving the deflecting means includes a reciprocating cam; and

b. means are provided for translating the cam motion to motion of the bending roll relative to the guide rolls.

11. Apparatus for coiling continuously supplied material as defined in claim 10 and further including a hydraulic cylinder enclosing a piston, and a shaft connecting the piston to said cam, whereby reciprocation of the piston by means of hydraulic pressure reciprocates the cam.

12. Apparatus for coiling continuously supplied material as defined in claim 11 and further including:

a. means for slidably supporting the cam and for fixedly supporting the hydraulic cylinder; and

b. means for moving the supporting means of subparagraph (a) with respect to the bending roll.

13. Apparatus for coiling continuously supplied elongated material as defined in claim 11 wherein the control means comprises:

a. means for causing the piston of the hydraulic cylinder to move in one direction for a first predetermined time interval and at a predetermined speed;

b. means for subsequently causing the piston to remain stationary for a second predetermined time interval;

c. means for subsequently causing the piston to move fora third time interval equal to the first predetermined lime interval and at the same speed, but in the opposite 

1. A method of coiling elongated material comprising the steps of: a. supplying a continuous length of the material at constant speed; b. bending the material prior to its reaching its final position in the coil at constant bending radius until one complete convolution of bent material has been made; c. bending a subsequently supplied length of material at a bending radius varying linearly with time until at least one additional convolution coplanaar and continuous with the convolution made in the course of step (b) is made, whereby a radial layer is formed of the convolutions made in the course of steps (b) and (c); and d. bending a subsequently supplied length of material at constant bending radius different from that of step (b) until one complete convolution of a second radial layer has been made.
 2. A method of coiling continuous elongated material as defined in claim 1 comprising the additional subsequent step of: e. bending a continuous length of material at a bending radius varying linearly with time at the same rate as in step (c) but in a sense opposite to that of step (c) until at least another complete convolution has been made coplanar and continuous with the convolution made in the course of the step (d).
 3. A method of coiling elongated material comprising the steps of: a. bending a continuous length of material at a varying bending radius until one or more convolutions have been completed; and b. next bending a length of material continuous with the length of step (a) at a constant bending radius.
 4. A method as defined in claim 3, wherein the constant bending radius of step (b) is the same as the last value of varying bending radius of step (a).
 5. A method of coiling continuously supplied tubing into a continuous coil comprising the steps of: a. bending a length of tubing into a plurality of coplanar convolutions to make a first radial layer; b. concurrently supporting said first radial layer in a substantially horizontal plane; c. subsequently bending a length of tubing into a plurality of coplanar convolutions to make a second radial layer substantially of the same radial dimension as the first radial layer; and d. concurrently with step (c), positioning the convolutions of the second radial layer below the first radial layer, with each convolution of tubing in the second layer bearing against and pushing upwardly at least one convolution of tubing in the first layer whereby the coil is built in the upward direction.
 6. A method of coiling tubing as in claim 5, including the additional subsequent step of bending tubing into additional pluralities of convolutions for making additional radial layers, each substantially of the same radial dimension as that of previously made radial layers, and positioning each radial layer below the previously made radial layer in the same manner as the second radial layer was positioned underneath the first radial layer.
 7. Apparatus for coiling continuously supplied elongated material comprising: a. means for bending the supplied material at predetermined bending radii; and b. control means for alternately keeping the radius at which the bending means bends the material constant for predetermined periods of time and varying for predetermined periods of time.
 8. Apparatus for coiling continuously supplied elongated material as defined in claim 7, wherein the bending means comprises: a. means for confining the supplied material to a fixed path; b. means for deflecting the supplied material from its path as it leaves the confining means; and c. means for moving the deflecting means to different positions relative to the confining means.
 9. Apparatus for coiling continuously supplied material as defined in claim 8 wherein the confining means comprises: a. at least one opposed pair of guide rolls defining between them a passageway for the supplied material; and b. the deflecting means includes a bending roll.
 10. Apparatus for coiling continuously supplied material as defined in claim 9 wherein: a. the means for moving the deflecting means includes a reciprocating cam; and b. means are provided for translating the cam motion to motion of the bending roll relative to the guide rolls.
 11. Apparatus for coiling continuously supplied material as defined in claim 10 and further including a hydraulic cylinder enclosing a piston, and a shaft connecting the piston to said cam, whereby reciprocation of the piston by means of hydraulic pressure reciprocates the cam.
 12. Apparatus for coiling continuously supplied material as defined in claim 11 and further including: a. means for slidably supporting the cam and for fixedly supporting the hydraulic cylinder; and b. means for moving the supporting means of subparagraph (a) with respect to the bending roll.
 13. Apparatus for coiling continuously supplied elongated material as defined in claim 11 wherein the control means comprises: a. means for causing the piston of the hydraulic cylinder to move in one direction for a first predetermined time interval and at a predetermined speed; b. means for subsequently causing the piston to remain stationary for a second predetermined time interval; c. means for subsequently causing the piston to move for a third time interval equal to the first predetermined time interval and at the same speed, but in the opposite direction; and d. means for subsequently causing the piston to remain stationary for a fourth predetermined time interval.
 14. Apparatus for coiling continuously supplied material as defined in claim 11 wherein the control means comprises: a. means for causing the bending means to vary the bending radius at a predetermined rate of change; b. means for deactivating the means of subparagraph (a) for predetermined periods of time, whereby the bending means is caused to bend at constant bending radii during said predetermined periods of time. 